It occupies the east bank of the Killilagh River, and part of what once formed its enclosure has long since been absorbed into the surrounding field system, so that a modern boundary wall and ditch now stand in for sections of the original earthwork. The result is a monument that has, in a sense, been quietly cannibalised by the agricultural landscape growing up around it.

A rath, as this type of site is classified, is an earthen ringfort, a roughly circular enclosure defined by a raised bank and an outer ditch called a fosse, constructed during the early medieval period in Ireland, broadly between the fifth and twelfth centuries. They functioned primarily as enclosed farmsteads, the home of a single family and their livestock, and they are found in almost every county. The Lisnafulla example is modest in scale, measuring approximately 35 metres across in both directions, which places it at the smaller end of the spectrum. Its enclosing bank survives to an internal height of around 0.8 metres and an external height of 1.5 metres, with a fosse some 2.8 metres wide and 0.5 metres deep running alongside it. These measurements were recorded by Denis Power and uploaded to the survey record in August 2011. The bank runs from the north-northeast around to the south, where it gives way to a field boundary that continues the enclosure in two directions, eventually reaching the river's edge to the northwest.

Visitors approaching this site should be prepared for genuinely rough ground. The surrounding pasture is marshy, the bank itself is heavily masked by briars and dense scrub, and the interior, while under rough grass, has clusters of bramble along its inner edges. The fosse is partly obscured where a field boundary abuts it to the east-northeast. There is no formal access, and the site sits within working farmland, so landowner permission would be the sensible first step before attempting a close inspection. The best conditions for reading the earthworks are likely in late autumn or winter, when vegetation dies back enough to reveal the contours of the bank and the line of the fosse beneath the growth.